Vacuum pencil



2 Sheets-Sheet l QQ M k Q g u mm 8 w am w H. C. LERNER ET AL VACUUM PENCIL Aug. 29, 1967 Filed om. 2a, 1965 I) g M mNa w New 7 W 0 4 /7 M mw 5 7 a m Q. #m\

Aug. 29, 1967 H, L RNER 5 AL 3,337,897

VACUUM PENCIL 2 Sheets-Sheet 2 Filed Oct. 23, 1965 WW M 2 J7 M i MREEEEEZEQ E VEZZE United States Patent 3,337,897 VACUUM PENCIL Henry C. Lerner, Los Angeles, and Veron E. L0ng, Sherman Oaks, Calif., assignors to Engineering & Electronics Devices Inc., Los Angeles, Calif., a corporation of California Filed Oct. 23, 1965, Ser. No. 502,860 5 Claims. (Cl. 15-341) ABSTRACT OF THE DISCLOSURE A unitary, completely self-contained vacuum pencil for aspirating articles andfluids from confined spaces, including a pencil-like barrel adapted to be held in one hand of the user, a plunger movable longitudinally within the interior of the barrel, a spring which normally urges the plunger rearwardly inside the barrel, the rear end of the plunger being exposed so that it may be moved forward by finger pressure, a latch fastened to the exterior of the barrel for latching the plunger in a forward position, an open orifice at the forward end of the barrel for receiving the articles or fluids, a screening element disposed within the forward end of the barrel in a fixed position, and an ejector rod secured to the plunger and passing through an opening in the screening element and thus extending through the orifice when the plunger is in its forwardly extended position.

This is a continuation-in-part of our co-pending application, Ser. No. 455,347, filed May 12, 1965, and entitled, Vacuum Pencil.

This invention relates generally to vacuum devices or tools and has more particular reference to a novel unitary, completely self-contained vacuum pencil for retrieving small work parts and removing foreign matter, including both liquids and solids, from work areas, particularly confined work areas which are inaccessible to conventional vacuum tools for this purpose. I

The current trend in many phases of the electronics industry is in the direction of miniature and micro-miniature circuit components and assemblies. This trend, of course, is the result of the ever increasing demand for reduction in the size and weight of electronic equipment, particularly electronic assemblies for computers, aircraft, and space vehicles. In many cases, construction of such miniature and micro-miniature electronic assemblies requires soldering of a great number of electrical connections in relatively confined spaces. Soldering operations of this nature present two basic dilficulties, to wit, proper application of solder to each electrical connection and removal of any excess solder from each soldered connection. Moreover, during the construction of such assemblies, small work parts, such as miniature and microminiature circuit components are oftenaccidentally dropped into the interior recesses of the assemblies. These parts must be removed and are preferably retrieved for subsequent use. A variety of manual, semi-automatic, and fully automatic soldering devices have been devised which are capable of effectively soldering the many electrical connections in miniature and micro-miniature electronic assemblies. Insofar as I am aware, however, no practical devices have been devised for removing excess solder from the connections, or retrieving small work parts which are accidentally dropped into the assemblies. There are, of course, many devices available for this general purpose. These existing devices, however, are ill-suited to use on miniaturized electronic equipment, particularly micro-miniature electronic assemblies.

One of the existing devices for this purpose, for example comprises a vacuum nozzle which, in some cases,

may be mounted directly on a soldering tool and is connected to an external vacuum pump. These'vacuum devices, however, are bulky and require a hose connection to the external vacuum pump. As a consequence, the devices are ill-suited for use on miniaturized electronic assemblies. Moreover, it is impossible to retrieve small work parts with these existing vacuum devices since the parts are exhausted into a large filter bag, or the like, containing, in most cases, a large amount of solder and other debris. Another existing vacuum device for this general purpose comprises a self-contained vacuum unit which requires no hose connection to an external vacuum pump. This latter device, however, is also too large and bulky for use on miniaturized electronic assemblies and is hazardous to use. In addition, the existing vacuum devices are relatively heavy and cause rapid fatigue of the operator.

It is evident at this vacuum device for removing foreign matter and retrieving from miniature and microminiature electronic assemblies. This invention provides such an improved vacuum device, or vacuum pencil, as it is referred to herein. As will appear from the ensuing description, however, the vacuum pencil of the invention may be used for numerous other purposes.

It is a general object of the invention, therefore, to provide a novel vacuum pencil of the character described.

Another object of the invention is to provide a vacuum pencil which is relatively small and completely self-contained and, thereby, uniquely adapted for use on miniature and microminiature equipment, such as miniatuirzed electronic assemblies.

Yet another object of the invention is to provide a vacuum pencil which may be held in and operated by one hand.

An important object of the invention is to provide a vacuum pencil which is light weight, typically weighing on the order of l 02., and thus does not fatigue the operator.

A further object of the invention is to provide a vacuum pencil which is relatively simple in construction, economical to manufacture, reliable in operation, convenient to use, and otherwise ideally suited to its intended purpose.

With these and other objects in view, the invention consists in the construction, arrangement, and combination of the various parts of the device, whereby the objects contemplated are attained, as hereinafter set forth, pointed out in the appended claims, and illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a perspective view of a vacuum pencil according to the invention illustrating the pencil being gsed to remove excess solder from an electronic assem- FIGURE 1a is an enlarged fragmentary view, partly broken away, of the tip of the vacuum pencil showing the excess solder being aspirated into the pencil;

FIGURE 1b is a view similar to FIGURE 1a showing the solder being ejected from the pencil;

FIGURE 2 is an enlarged axial section through the pencil showing a certain plunger in the pencil in its retracted position;

FIGURE 3 is an axial section through the pencil, in a plane normal to the section in FIGURE 2, showing the plunger in its extended position;

FIGURE 4 illustrates a modified tip for the pencil;

FIGURE 5 is an axial section through a modified vacuum pencil according to the invention;

FIGURE 6 is an enlarged fragmentary section through a latch means embodied in a vacuum pencil of FIG- URES;

FIGURE 7 is a view looking in the direction of the arrows on line 77 in FIGURE 6, partially broken away for the sake of clarity;

FIGURE 8 is a fragmentary section similar to FIG- URE 6 illustrating the latch means in operative engagement with the plunger of the vacuum pencil; and

FIGURE 9 is a section taken on line 9-9 in FIG- URE 8.

The vacuum pencil 10 illustrated in FIGURES l-4 of the drawings comprises a relatively small, pencil-like barrel 12 which is typically on the order of six inches in length and one-half inch in diameter. The barrel is composed of three separable sections, to wit, a rear cylinder section 14, an intermediate coupling section 16, and a front tip section 18. The coupling section 16 has a front and rear, externally threaded extremities 20 and 22, respectively, and an intervening shoulder and flange 24. The rear end of the tip section 18 is internally threaded to receive the front extremity 20 of the coupling section. The front end of the cylinder section 14 is internally threaded to receive the rear extremity 22 of the coupling section. When the three barrel sections 14, 16, and 18 are assembled, the rear end face of the tip section and the front end face of the cylinder section seat against the front and rear faces, respectively, of the coupling flange 24.

Slidably fitted within the rear cylinder section 14 is a plunger 26. Plunger 26 comprises a sleeve 28 having a rear end wall 30 which seals the rear end of the plunger. The front end of the plunger is open. The rear end portion of the plunger 26 is exposed through an opening 32 in the rear end of the cylinder section 14. This opening extends laterally through the side wall and axially through the rear end of the cylinder section. The angular extent of the opening 32, measured circumferentially of the cylinder section 14, is somewhat less than 180 degrees. The axial length of the opening is somewhat less than the length of the plunger 26. Accordingly, the rear end portion of the plunger, while being exposed through the opening 32, is slidably confined by the cylinder section. The cylinder section has a rear, inwardly directed lip or shoulder 34 which limits rearward movement of the plunger in the barrel 12.

Extending coaxially from and secured to the rear end of the coupling section 16 is a sleeve 36. The diameter of this sleeve is substantially less than the internal diameter of the plunger 26. Sleeve 36 extends rearwardly from the coupling section to a position about midway between the ends of the cylinder section 14. The central passage in the sleeve opens rearwardly through the rear end of the sleeve and forwardly through the coupling section 16 into a chamber 38 within tip section 18. Opening through the wall of this sleeve is an axially extending slot 40.

Extending axially through the sleeve 36 and forwardly therefrom, through the coupling section 16 into the chamber 38 within the tip section 18, is an ejector rod 42. Rod 42 has a rear head 44 with a detent 45 which engages in the sleeve slot 40. Encircling the ejector rod 42, between the latter and the wall of the sleeve 36, is a compression spring 46. The ejector rod head 44 engages between two adjacent turns of this spring as shown. At its forward end, the spring 46 seats against a rearwardly presented shoulder 48 on the coupling section16. The rear end portion of this spring extends rearwardly from the sleeve 36 into contact with the plunger end wall 30.

Spring 46 urges the plunger to its rear retracted position of FIGURE 2, wherein the plunger seats against the rear barrel shoulder 34. The plunger is movable for wardly in the barrel 12, against the action of spring 46, to its forward extended position of FIGURE 3, wherein the front end of the plunger is located adjacent the coupling section 16. It is significant to note at this point that forward movement of the plunger in the barrel compresses the spring 46 and thereby moves the ejector rod 42 forwardly in the barrel. It should also be noted that rotation of the spring in one direction advances the rod forwardly in the barrel. Rotation of the spring in the opposite direction retracts the rod rearwardly. Thus, the axial position occupied by the rod when the plunger 26 is extended may be adjusted by rotation of the spring. In practice, the rod is axially adjusted so that its forward tip projects through a suction opening or' orifice 50 in the front end of the tip section 18 to a position wherein the tip of the rod is about flush with the front end of the tip section when the plunger is extended.

Slidably positioned on the ejector rod 42, forwardly of the coupling section 16, is a screening element 51. As will appear shortly, the purpose of this screening element is to permit air flow through the central opening in the coupling section 16 while preventing passage through said opening of articles aspirated into the forward chamber 38 of the vacuum pencil.

Barrel 12 carries an externally operable latch means 52 for releasably latching the plunger 26 in its forward extended position. This latch means comprises a spring blade 54, the ends of which are bent in opposite transverse directions to form front and rear shoulders 56 and 58. The front end of the blade seats in an external axial slot 59 in the rear extremity 22 of the coupling section 16 and is confined between the latter section and the cylinder section 14. The front shoulder 56 on the blade 54 engages in a recess 60 at the forward end of the slot to confine the blade again'st endwise movement.

The rear shoulder 58 on the spring blade 54 forms a latch shoulder. This latch shoulder is engageable with a cooperating internal rearwardly presented latch shoulder 62 in the forward end of the plunger 26 when the latter occupies its forward extended position.

The blade is biased to normally retain its latch shoulder 58 in latching engagement with the plunger latch shoulder 62, thereby to retain the plunger in its forward extended position. Seating against and preferably secured to the outer surface of the spring blade 54 is a button 64 which protrudes through an opening in the front end of the cylinder section 14. Pressure on this button deflects the blade inwardly to retract its latch shoulder 58 out of latching engagement with the plunger latch shoulder 52. The plunger is thereby released for rearward movement in the barrel 12 under the action of the plunger spring 46. The front end of the plunger is internally beveled at 66 to deflect the latch plate 54 inwardly during subsequent forward extension of the plunger thereby to reengage the latch shoulder 58 on the blade with the latch shoulder 62 on the plunger. Plunger 26 has a rear knurled finger piece 67 which projects through the barrel opening 32.

In use, the barrel 12 of the present vacuum pencil 10 is grasped in one hand and a finger is pressed against the rear, exposed finger piece 67 on the plunger 26 to move the latter to its forward extended position in the barrel against the action of the plunger spring 46. The plunger is latched in this position by the latch means 52. Subsequent depression of the latch button 64 releases the latch means, whereupon the plunger 26 is propelled rearwardly in the barrel 12 by the compressed plunger spring. This rearward movement of the plunger in the barrel aspirates air into the pencil thru the orifice or suction opening 50.

When removing or retrieving an object, such as a micro-miniature component or a fluid such as liquid solder, from a work area, the plunger 26 is latched in its forward extended position and the tip of the vacuum pencil is placed in close proximity to the item to be removed or retrieved, as shown in FIGURES 1 and 1a. The latch button 64 is then depressed with one finger of the hand which grasps the pencil, thereby to release the plunger for rearward movement in the barrel 12.. The resulting pressure drop in the front pencil chamber 38 causes an inrush of air into the chamber through the front suction opening 50 in the pencil, which aspirates the item into the chamber. The retrieved item may be removed from the chamber in various ways. For example, the front tip section 18 of the vacuum pencil may be removed and may be externally knurled for this purpose. Alternatively, the vacuum pencil may be held in an upright position to cause the item to move to a position adjacent the inner end of the suction opening 50. The ejector rod 42 may then be extended forwardly, to eject the item through the suction opening, as shown in FIGURE lb, by depressing the plunger 26 to its forward extended position.

In the event that the vacuum pencil is to be employed for removing excess solder from miniature and micro-miniature electronic assemblies, for example, the tip section 18 is constructed of a high temperature resistant material to which the solder Will not adhere, such as Teflon, and is provided with an elongate suction opening 50, as in FIGURES 2 and 3, which is proportioned to contain the entire quantity of excess solder which is removed during each operation of the vacuum pencil. In this case, the solder solidifies in the suction opening and may be subsequently ejected from the opening by the ejector rod 42, in the manner explained above. The diameter of the ejector rod is preferably somewhat less than the diameter of the suction opening in this case, to permit aspirating air flow into the forward pencil chamber 38 immediately upon rearward retraction of the plunger 26 in the pencil barrel 12. In the event that the present vacuum pencil is to be employed primarily for retrieving solid objects, such as micro-miniature components, the suction opening 50 may have a relatively short axial length, as in FIGURE 4.

It is apparent that when the plunger 26 retracts rearwardly in the barrel 12 under the action of the plunger spring 46, to aspirate an item into the forward pencil chamber 38, air flow occurs from the chamber, through the central opening in the coupling 16, into the cylinder section 14. This air flow tends to draw the retrieved item into the cylinder section, which is undesirable. The screening element 51 is provided to confine the retrieved item in the forward pencil chamber 38 while permitting aspirating' air flow from the chamber into the cylinder section. This screening element may comprise a small porous washer constructed of steel fibers, for example.

At this point, it is significant to note that the present vacuum pencil 10 is adapted to be held in and operated by one hand. The pencil is, therefore, convenient to use. It should also be noted that the small size of the pencil and the taper of its tip section 18 uniquely adapts the pencil for use on miniature and micro-miniature electronic assemblies. The pencil may be provided with a pocket clip 68.

Reference is now made to FIGURES 5 through 9, illustrating a more highly refined embodiment of the present vacuum pencil, which possesses certain advantages over the vacuum pencil described earlier, notably greater simplicity of construction and economy of manufacture. The modified vacuum pencil 100 is generally similar to the earlier vacuum pencil and comprises two separable sections, to wit, a rear cylinder section 104 and a front tip section 106. The front end of the rear cylinder section 104 is internally threaded at 108 at receveice a rear, reduced threaded extremity 110 on the tip 106. Preferably, the threads 108 comprise modified acme threads of relatively large pitch and having flat tips disposed flush with the inner surface of the rear cylinder section 104. Threads of large pitch are preferably employed to permit the tip 106 to be quickly removed from and reassembled on the rear cylinder section.

Slideably fitted within the rear cylinder section 104, is a plunger 112. Plunger 112 comprises a sleeve, the rear end of which is closed by a plug 114. Plug 114 has an intermediate cylindrical portion 116 and front and rear cylindrical ends 118 and'120, respectively, of reduced diameter relative to the central portion 116. The

6 juncture of the central portion 116 and the front end 118 ofthe plug 114 defines an annular, forwardly presented shoulder 122 on the plug. The juncture of the central portion 116 and the rear end of the plug defines an annular, rearwardly presented shoulder 124 on the plug. The central portion 116 of the plug is dimensioned to have a light press fit within the plunger 112. When assembling the plug 114 to the plunger 112, the plug is driven into the plunger in a position wherein the rear plug shoulder 124 is located a small distance inwardly or forwardly of the rear end of the plunger. The rear end of the plunger is then turned inwardly to form an internal shoulder 126 on the plunger, which seats axially against the plug shoulder 124 and radially against the rear plug end 120. The front end of the plunger 112 is open. Formed in the external surface of the plunger, adjacent its front end, is an annular groove 128. This groove defines an annular, rearwardly presented shoulder 130 at the front end of the plunger.

Plunger 112 is exposed through a slot or opening 132 and the rear end of the rear cylinder section 104. This opening extends laterally through the side wall and axially to the rear end of the cylinder section. The angular extent of the opening 132, measured circumferentially of the cylinder section 104, is somewhat less than 180 degrees. The axial length of the opening is somewhat less than the length of the plunger 112. Accordingly, the plunger, while exposed through the opening 132, is Slideably confined by the cylinder section. The rear end of the cylinder section is turned inwardly to form a shoulder 134, which limits rearward movement of the plunger in a cylinder section. v

Concentrically disposed within the front end of the rear cylinder section 104 is a generally conical spring 136 which tapers to a smaller diameter toward the rear end of the section. Spring 136 is wound in the proper direction and properly dimensioned, to mate at its front, large diameter end, with the internal threads 108 in the front end of the cylinder section. Accordingly, the spring may be threaded into the front end of the cylinder section. The spring is thus inserted into the cylinder section to a position wherein the front end of the spring seats within a relief groove 137 at the rear end of the cylinder threads 108. Preferably, the front end of the spring is secured to the cylinder section in any convenient way, as by adhesively bonding the spring to the section. Several adjacent coils at the rear, small diameter end of the spring 136 have substantially the same diameter and together define an effective bearing bore 138 centered on the axis of the cylinder.

Extending centrally through the cylinder 104 and the plunger 112 is a coil spring 140. One end of the coil spring 140 seats against the outer surface of the conical spring 136 at a position intermediate the ends of the latter spring. The rear end of the spring 140 encircles the front end 118 of the plunger plug 114 and seats against the forwardly presented plug shoulder 122. Spring 140 is axially dimensioned to urge the plunger 112 to its rear limiting position of FIGURE 5, wherein the plunger seats against the rear shoulder 134 on the cylinder 104.

In the event that the vacuum pencil 100 is to be employed to remove excess solder from electronic assemblies, and the like, the tip 106 is preferably constructed of high temperature resistant material to which the solder will not adhere, such as Teflon. Extending axially through the tip is a stepped bore 142. This bore decreases in diameter toward the front end of the tip and terminates, at its forward end, in a relatively small diameter orifice 144. The rear end of the bore 142 opens to the interior of the cylinder 104. Preferably, the tip 106 is externally tapered, like the tip of the vacuum pencil described earlier.

Plunger 112 is movable forwardly in the cylinder 104 to its forward extended position of FIGURE8, wherein the front end of the plunger is telescoped over the rear 7 end of the conical spring 136 and is located adjacent the rear end of the tip 106. Latch means 146 are provided for releasably latching the plunger in this extended position. Latch means 146 comprises a latch member 148 which is pivotally mounted intermediate at its ends on the cylinder 104 for pivotal movement between its latching position of FIGURES 6 and 8, wherein the front end of the member projects into the central opening'or bore in the cylinder, and a retracted position, wherein the front end of the member is s =bstantially flush the wall of the cylinder bore. As will appear from the following description, the latch member is resiliently biased to its latching position. Latch member 148 may be pivotally mounted on the cylinder 104 in various ways. According to the preferred practice of the invention, however, the latch member is integrally formed with the cylinder by routing or otherwise cutting a pair of overlapping, generally U shaped slots 150 and 152 in the wall of the cylinder in such a way as to define a latch member of generally T shape and a pair of resiliently flexible connecting portions 154 extending rearwardly from and integrally joining the outboard ends of the forward cross arm of the T to the Wall of the cylinder proper. The connecting portions 154 are located intermediate the front and rear ends of the latch member 148 and pivotally mount the latch member on the cylinder for pivotal movement about an effective pivot axis extending transversely of the cylinder. After cutting the slots 150, 152 the front ends of the resiliently flexible connecting portions 154 are bent inwardly slightly to resiliently retain the latch member 148 in its latching position in FIGURES 6 and 8.

When the plunger 112 is pushed forwardly in the cylinder 104 to its extended position in FIGURE 8, the front shoulder 130 on the plunger initially engages the inwardly projecting front end of the latch member 148 and urges this end of the member outwardly against the spring action of the resiliently flexible connecting portions 154 of the latch. The latch member thereby exerts a lateral thrust on the front end of the plunger which urges the latter into frictional engagement with the opposite inner wall of the cylinder 104. The plunger spring 140 may be selected to have a spring rate, such that this frictional engagement of the plunger with the cylinder is effective to retain the plunger in its extended position. If desired, however, the plunger may be positively latched in its extended position by pushing the plunger forwardly in the cylinder until the front, inwardly projecting end of the latch member 148 snaps behind the plunger shoulder a 130, as illustrated in FIGURE 8. In either case, the

plunger is released for return to its rear limiting or retracted position of FIGURE 5, under the action of the plunger spring 140, by pressing on the rear end of the latch member 148. Thus, pressure on the rear end of the latch member causes flexing of the resiliently flexible portions 154 in such a way that the latch member pivots on its effective axis in a direction to retract the front end of the member out of latching engagement with the plunger. The plunger is then returned to its retracted position of FIGURE 5, by the action of the plunger spring 140. In order to avoid excessive local wear of the plunger shoulder 130 by repeated engagement of the shoulder with the latch member 148, it is desirable to periodically rotate the plunger in the cylinder 104, thereby to periodically present a new portion of the shoulder to the latch member.

The vacuum pencil 100 is used in the same way as the vacuum pencil described earlier. Thus, the plunger 112 of the vacuum pencil 100 is latchedjin its extended position and the front end of the orifice 144 in the tip 106 is placed in close proximity to the object or material to be picked up. The rear end of the latch member 148 is then depressed to release the plunger for retraction in the cylinder 104 under the action of the plunger spring 140.

During this retraction of the plunger, air is drawn into 106. When the plunger the pencil through the orifice 144, thereby aspirating the object or material into the pencil through the orifice.

It is apparent, of course, that eflicient operation of the pencil requires sealing of the cylinder slots and 152 against air flow therethrough during retraction of the plunger. To this end, the portion of the cylinder 104 containing the latch means 146 is enclosed in a sealing sleeve 156, which is sealed to the wall of the cylinder forwardly and rearwardly of the latch means. Sleeve 156 is constructed of a flexible material which permits depression of the rear end of the latch member 148, to release the plunger 112, by the application of pressure to the sleeve 156 over the rear end of the latch end. Preferably, the sleeve is marked, as by a small colored dot 158 and the illustrated Word Press, to indicate the position at which pressure should be applied to the sleeve to release the latch member 148. The sealing sleeve 156 may be constructed in various ways. For example, the sleeve may comprise a length of pressure sensitive plastic tape, or the like, which is wrapped around the cylinder 104. According to the preferred practice of the invention, however, the sealing sleeve comprises a length of so called shrink tubing, which is shrunk onto the cylinder 104 about the latch means 146. A sealing sleeve of this type is preferred for the reason that it is more durable than pressure sensitive tape, for example, and cannot be removed to expose the latch means 146 without destruction of the sleeve.

It is significant to note that when, in its forward extended position of FIGURE 8, the plunger 112 limits inward deflection of the rear end of the latch member 148. Accordingly, the plunger when extended, is effective to prevent excessive inward deflection of the latch member which would cause stressing of the resiliently flexible connecting portions 154 beyond their elastic limit and thereby, permanent deformation of the portions. It is possible, however, that a person using the vacuum pencil 100 may inadvertently exert pressure on the rear end of the latch member 148 while the plunger 112 is retracted. In this case, there is a possibility that the latch member may be depressed to such an extent that the connecting portions 154 of the latch member, are permanently deformed sufficiently to destroy the proper latching action of the member. For this reason, the illustrated vacuum pencil 100 is equipped with spring means 160 for preventing excessive inward deflection of the rear end of the latch member. The illustrated spring means 160 comprises a band of resiliently flexible material, such as Milar, which encircles the cylinder 104 in underlying relation to the rear end of the latch member. Accordingly, inward pressure on the rear end of the latch member effects engagement of the member with the band 160, which thereby limits inward deflection of the rear end of the member. Other'types of spring means, other than the illustrated band 160, may be employed for this purpose, such as a spring ring, or the like.

Extending axially through the barrel 102 is an ejector rod 162. The rear end of this rod is fixed within a cen-. tral bore in the plunger plug 114. The forward end of the rod extends slideably through the effective bearing bore .138 defined by the conical spring 136. Rod 162 is dimensioned to fit slideably within the orifice 144 in the tip 112 is retracted, the front end of the ejector rod is located within the rear end of the conical spring 136. During forward movement of plunger in the cylinder 104, to its extended position of FIGURE 8, the front end of the rod enters the orifice 144 to eject therefrom any objects or material, such as solidified solder, present in the orifice.

It is now evident that the operation of the modified vacuum pencil 100 is essentially the same as the operation of the vacuum pencil described'earlier. Accordingly, it is unnecessary to repeat, in detail, the operation of the modified vacuum pencil. It is significant to note, howpose. First, this spring provides a bearing which slideably supports the ejector rod 162 during axial movement of the rod in the barrel 102 with the plunger 112. Secondly, the spring serves as a filter which permits air flow between the cylinder 104 and the tip 106 during extension and retraction of the plunger 112, but blocks the entrance into the cylinder of the various objects and materials which are aspirated into the pencil during operation thereof. In this regard, it is significant to note that during retraction of the plunger in the cylinder 104 under the action of the plunger spring 140, a pressure differential is created across the conical spring 136 which tends to extend the latter and thereby separate the adjacent spring coils to permit free flow of air through the spring. However, the spring coils do not separate sutficiently to permit passage therebetween of the objects and materials aspirated into the pencil. If desired, a conically tapered brush, or the like, may be furnished with the vacuum pencil 100 for the purpose of cleaning the interior surfaces of the tip 106 and the conical spring 136.

One highly important advantage of the present vacuum pencil resides in the fact that the pencil is small in size and light in weight and thus may be used for extended periods of time without causing fatigue of the operator. A typical vacuum pencil, according to the invention, for example, weighs on the order of 1 oz. Another advantage of the vacuum pencil is that after retrieving a small fork part, such as a micro-miniature circuit component, by aspirating the part into the pencil, the pencil tip may be immediately pointed upwardly and the plunger may be latched in its extended position wherein the ejector rod closes the pencil orifice, thereby to trap the part in the forward pencil chamber until the part is deliberately removed by releasing the plunger, pointing the tip downwardly, and shaking the pencil or removing the tip.

While the invention has herein been shown and described in what is conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of the invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices.

Having described the invention, what is claimed as new in support of Letters Patent is:

1. A unitary, completely self-contained vacuum penoil for aspirating articles and fluids from confined spaces, comprising:

a relatively small, slender, pencil-like barrel adapted to be held in one hand, said barrel having front and rear ends and an orifice opening through said front ends;

" aplunger movable in said barrel;

a spring acting between said barrel and plunger for urging said plunger rearwardly in said barrel, the rear end of said plunger being exposed at the rear end of said barrel for forward movement of said plunger to a forward extended position in said barrel against the action of said spring by finger pressure on the exposed rear end of said plunger;

latch means operable externally of said barrel for latching said plunger in said forward extended position;

an ejector rod operatively connected to said plunger and movable forwardly in said barrel with said plunger to a position wherein the forward end of said rod extends into said orifice when said plunger occupies said forward extended position thereof;

and a screening element disposed within said barrel in surrounding relation to said ejector rod between said orifice and plunger, said screening element being pervious to air but impervious to articles and fluids aspirated into said pencil.

2. A unitary, completely self-contained vacuum pencil for aspirating articles and fluids from confined spaces, comprising:

a relatively small, slender, pencil-like barrel adapted to be held in one hand and including a rear cylinder section and a front hollow tip section removably secured to the front end of said cylinder section;

a plunger slidable in said cylinder section;

a spring acting between said cylinder section and plunger for urging the latter rearwardly in said cylinder section;

means on said cylinder section for limiting rearward movement of said plunger in said cylinder section, said cylinder section having a rear opening extending laterally through the side wall and axially through the rear end of said cylinder section and exposing the rear end of said plunger for forward movement of said plunger to a forward extended position in said cylinder section by finger pressure on the rear exposed end of said plunger;

externally operable latch means in said cylinder section for releasably latching said plunger in said forward extended position thereof;

an ejector rod operatively connected to said plunger and movable forwardly in said barrel with said plunger to a position wherein the forward end of said rod extends into said orifice when said plunger occupies said forward extended position thereof;

and a screening element disposed within the forward end of said cylinder section in surrounding relation to said ejector rod, said screening element being pervious to air but impervious to articles and fluids aspirated into said pencil.

3. A unitary, completely self-contained vacuum pencil for aspirating articles and fluids from confined spaces, comprising:

a relatively small, slender, pencil-like barrel adapted to be held in one hand, said barrel having front and rear ends and an orifice opening through said front end;

a plunger movable in said barrel;

a spring acting between said barrel and plunger for urging said plunger rearwardly in said barrel, the rear end of said plunger being exposed at the rear end of said barrel for forward movement of said plunger to a forward extended position in said barrel against the action of said spring by finger pressure on the exposed read end of said plunger;

latch means operable externally of said barrel for latching said plunger in said forward extended position thereof;

a screening element disposed within said barrel between said orifice and plunger, said screening element comprising a coil spring with normally contacting coils which is pervious to air but impervious to articles and fluids aspirated into said pencil;

said screening spring comprising a conical spring the diameter of which decreases toward the rear end of said barrel and which terminates at its rear end in a number of coils of substantially equal diameter defining an eifective bearing bore on the axis of said barrel;

an injector rod operatively connected to said plunger and movable forwardly in said barrel with said plunger to a position wherein the forward end of said rod extends into said orifice when said plunger occupies the forward extended position thereof;

said rod extending slidably through said bearing bore whereby said conical spring slidably supports said ejector rod during axial movement of the rod with said plunger.

4. A unitary, completely self-contained vacuum pencil for aspirating articles and fluids from confined spaces, comprising:

a relatively small, slender, pencil-like barrel having front and rear ends and adapted to be held in one hand, said barrel including a rear cylinder section, an intermediate coupling section, and a front tip section, said coupling section having a rear extremity threaded in the forward end of said cylinder section and a forward extremity threaded in the rear end of said tip section, said tip section having an internal threads in said cylinder section, saidspring decreasing in diameter toward the rear end of said cylinder section and terminating at its rear end in a number of coils of substantially equal diameter defining an chamber and a forward orifice opening through the effective bearing bore on the axis of said barrel, a front end of said tip section and communicating with cylindrical coil spring seating at one end against the said chamber, said coupling section having a cenouter surface of said conical spring and at the other tral opening communicating said chamber to the inend against the Closed rear end of Said Phlhgef for terior of said cylinder section, a plunger movable urging Said P r reafwafdly in Said barrel, Said in said cylinder section comprising a sleeve having cylinder section having a rear opening extending an open forward end and a closed rear end, a spring laterally through the side wall and axially through acting between said coupling section and said plunger the rear end of ai ylinder S ti n f r xp sing for urging said plunger rearwardly in said cylinder the Iear end of Said Plunger for forward movement section, said cylinder section having a rear opening of Said P g to a forward eXtehded P s n n extending laterally through the side wall and axially 15 Said barrel y g r Pr ss r n th r ar exposed through the end of said cylinder section for exposing end of Said P a shoulder on the real end of the rear end of said plunger for forward o t; said cylinder section for limiting rearward movement of said plunger to a forward extended position in of Said Plunger in Said barrel, ah elector Tod Secured said barrel against the action of said spring by finger t0 the rear end of Said Plunger and extending axialpressure on the rear exposed end of said plunger, y through Said barrel for a l e ent in said said cylinder section having a rear shoulder for limitbarrel With Said p unger, Said ejector rod being moving rearward movement of said plunger in said cylable forwardly in Said barrel to 3 Position wherein inder section, an ej to d t di i ll the forward end of said rod extends into said orifice through said barrel and having a rear enlarged head when Said Phlhgef occupies Said forward eXteHded engaging between two adjacent turns of said spring, position thereof, Said elector extending through whereby said rod undergoes axial movement in said and being 3 Supported in Said efieetive rbarrel with said plunger, said rod being movable ihg bore, the Well of Said cylinder Section having forwardly in said barrel with said plunger to a posiv l pping ge erally U shaped slots defining a tion wherein the front end of said rod extends into generally Shape latch member and resiliently said orifice when said plunger occupies said forward flexible eohheetihg Portions joining Said latch extended position thereof, a screening element dishe! to the Wall of Said cylinder Section, Said COhheetposed within said coupling section in surrounding reing Portions P y mounting Said latch member lation to said ejector rod, said screening element 011 Said eyhhdel Section rocking movement being pervious to air but impervious to articles and tween a latching Position Wherein the front end 0f fluids aspirated into said pencil, said plunger 1 the latch member is disposed within said cylinder ing a forward internal, re rw dl Presented latch section for latching engagement with the front end shoulder, a latch member mounted within the forof Said phlhgel' when said Phlhger occupies Said f Ward end of id cylinder gction f latching ward extended position thereof, and a retracted posigagement ith id h ld h id plunger tion wherein the front end of said latch member is cupies forward extended position thereof, said latch 40 disposed to release Said Plunger r m vemember being movable inwardly out of latching enmeht in said barrel, Said connecting Portions being gagement with said shoulder, thereby to release said Stressed to Yieldably urge Said latch member to Said plunger for rearward movement in said barrel, and latching 'P and the rear end of Said latch ha latch actuating member operatively engaging said her being disposed to receive fihgel' Pressure r latch member and projecting externally of said barrel rocking Said latch member to Said Iettaeted P through an opening in said cylinder section to receive finger pressure for moving said latch member inwardly out of latching engagement with said plunger.

tion thereof, a yieldable sealing sleeve surrounding said cylinder section in the region of said slots and latch member and sealed to said cylinder section at opposite ends of said latch member, and said latch member being pivotally movable to said retracted position thereof by application of finger pressure to said sealing sleeve over the rear end of said latch member.

5. A unitary, completely self-contained vacuum pencil for aspirating'articles and fluids from confined spaces, comprising:

a relatively small, slender, pencil-like barrel having front and rear ends and adapted to be held in one hand, said barrel including a rear cylinder section and a front tip section threaded in the forward end References Cited UNITED STATES PATENTS of said cylinder section, said tip section having an 1,020,935 3/1912 Jon s 128-297 internal chamber opening to said cylinder section 1,329,534 2/ 9 M-cGl'ath 43-135 and an orifice extending axially thru' the front end 1,797,557 3/ 1931 Stine et 8 of said tip section and communicating to said cham- 2,360,051 9 EWeSon 128297 her, a conical spring disposed within the forward 2,539,346 1/1951 L is et a1. l28297 X end of said cylinder section and having normally FOREIGN PATENTS contacting coils, the forward end of said spring seat 766,279 1/1957 Great Britaining in an internal relief groove within the forward end of said cylinder section at the rear end of the ROBERT W. MICHELL, Primary Examiner. 

1. A UNITARY, COMPLETELY SELF-CONTAINED VACUUM PENCIL FOR ASPIRATING ARTICLES AND FLUIDS FROM CONFINED SPACES, COMPRISING: A RELATIVELY SMALL, SLENDER, PENCIL-LIKE BARREL ADAPTED TO BE HELD IN ONE HAND, SAID BARREL HAVING FRONT AND REAR ENDS AND AN ORIFICE OPENING THROUGH SAID FRONT ENDS; A PLUNGER MOVABLE IN SAID BARREL; A SPRING ACTING BETWEEN SAID BARREL AND PLUNGER FOR URGING SAID PLUNGER REARWARDLY IN SAID BARREL, THE END OF SAID BARREL FOR FORWARD MOVEMENT OF SAID PLUNGER TO A FORWARD EXTENDED POSITION IN SAID BARREL AGAINST THE ACTION OF SAID SPRING BY FINGER PRESSURE ON THE EXPOSED REAR END OF SAID PLUNGER; LATCH MEANS OPERABLE EXTERNALLY OF SAID BARREL FOR LATCHING SAID PLUNGER IN SAID FORWARD EXTENDED POSITION; AN EJECTOR ROD OPERATIVELY CONNECTED TO SAID PLUNGER AND MOVABLE FORWARDLY IN SAID BARREL WITH SAID PLUNGER TO A POSITION WHEREIN THE FORWARD END OF SAID ROD EXTENDS INTO SAID ORIFICE WHEN SAID PLUNGER OCCUPIES SAID FORWARD EXTENDED POSITION THEREOF; AND A SCREENING ELEMENT DISPOSED WITHIN SAID BARREL IN SURROUNDING RELATION TO SAID EJECTOR ROD BETWEEN SAID ORIFICE AND PLUNGER, SAID SCREENING ELEMENT BEING PERVIOUS TO AIR BUT IMPERVIOUS TO ARTICLES AND FLUIDS ASPIRATED INTO SAID PENCIL. 